Wind Turbine Reactive Power Control via Dynamic Interval

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Solution Overview

Problem

Existing wind turbine operation methods are limited in generating reactive power independently of wind conditions, leading to potential overloading and inefficiencies in power distribution, especially during partial load operations.

Innovation Solution

A method for operating wind turbines with controllable active power, where each active power value is assigned a reactive power interval, allowing the actual reactive power to be controlled within this range, prioritizing reactive power over active power if necessary, and specifying target reactive power through a wind turbine controller or external sources.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the reactive power is determined by specifying a power factor that covers a specific value range, then the electrical components can be designed to withstand the load, but the maximum possible reactive power cannot be generated in partial load operation

Engineering Contradiction:
Improveelectrical component load withstand capabilityVSAvoidreactive power generation capability
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent applies dynamics by making the reactive power output dynamically adjustable within a calculated interval rather than fixed by a constant power factor. The controller dynamically determines the reactive power interval based on current active power output and component thermal capacities, allowing the system to adapt reactive power generation to varying load conditions while maintaining component safety margins.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter control approach from a fixed power factor to a variable reactive power interval defined by minimum and maximum reactive power values. This parameter change enables the system to generate maximum possible reactive power at each operating point while ensuring electrical components remain within safe thermal limits, resolving the contradiction between reliability and productivity.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the active power is limited to a maximum value to protect the wind turbine from overloading, then the turbine is protected, but the reactive power output is restricted when higher reactive power is needed for grid support

Engineering Contradiction:
Improvewind turbine overload protectionVSAvoidreactive power output capability
Core Design Contradiction:
ReliabilityVSPower

Solution Approach 1:

The patent segments the power output control into independent active power and reactive power components. By calculating a reactive power interval based on the vector relationship between active power, reactive power, and apparent power limits, the system can independently optimize reactive power output within safe operational boundaries without being constrained by active power generation levels.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system dynamically adjusts the reactive power output within a calculated interval that varies with active power levels. This dynamic approach allows maximum reactive power generation when grid support is needed while automatically maintaining protection against overloading, resolving the contradiction between reliability and power output capability.

Inventive Principle:
Principle #15Dynamics

3Ease of operation

If a constant apparent power is established independent of available wind, then the reactive power regulation is simplified, but the reactive power output is limited when higher reactive power is required

Engineering Contradiction:
Improvereactive power regulation simplicityVSAvoidreactive power output availability
Core Design Contradiction:
Ease of operationVSPower

Solution Approach 1:

The patent replaces constant apparent power control with dynamic reactive power interval control. The controller continuously calculates the reactive power interval based on current operating conditions, active power output, and component thermal capacities, enabling the system to provide maximum available reactive power while maintaining simplified automated regulation without requiring complex manual intervention.

Inventive Principle:
Principle #15Dynamics

4Loss of energy

If the reactive power is regulated as a function of active power to maintain constant apparent power, then the power distribution is optimized, but the reactive power cannot be increased independently to support grid voltage

Engineering Contradiction:
Improvepower distribution efficiencyVSAvoidindependent reactive power support capability
Core Design Contradiction:
Loss of energyVSPower

Solution Approach 1:

The patent segments the control objectives by allowing independent optimization of reactive power within a safety-defined interval. The system maintains efficient power distribution through the reactive power interval calculation while enabling independent reactive power adjustment within this interval to provide grid voltage support when needed, resolving the contradiction between distribution efficiency and independent reactive power support.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP1892412B1Method for operating wind farms
Publication Date: 2011.07.27 NORDEX ENERGY
  • EP1892412B1 patent drawingFigure 1
  • EP1892412B1 patent drawingFigure 2
  • EP1892412B1 patent drawing

AI summary

Method for operating a wind turbine with controllable active power, wherein each value of the active power is assigned a reactive power interval defined by a minimum reactive power and a maximum reactive power, and the actual reactive power is controllable within this interval, characterized in that the active power is reduced when a target reactive power lies outside the reactive power interval assigned to the current active power.